Undead enhancement (3.5 spell)

[Alex12]

So in our current campaign, my backup character plan is a Necropolitan Dread Necromancer, but the DM said I can't just get the effects of being created with Corpsecrafter without paying for them. This is how I plan on doing that.
I just wanted to get the playground's opinion on this. Broken? Not broken? A terrible idea?

Enhance Undead
Necromancy
Level: Clr 3, Sor/Wiz 4, Dread Necromancer 4
Components: V, S, M/DF
Casting Time: 1 hour
Range: Touch
Target: One willing or helpless undead creature
Duration: Instantaneous
Saving Throw: Yes (potentially harmless, see text)
Spell Resistance: Yes (potentially harmless, see text)

You finish the ritual, crushing the bone and spreading the dust on the undead before you. A faint aura flickers briefly around it, before seeming to be absorbed.
This spell allows the caster to apply abilities to an undead creature that can normally only be applied at creation. At the end of the casting, the caster may choose to apply any undead enhancement abilities that he has access to (such as Corpsecrafter, the Dread Necromancer's Undead Mastery ability, or the effect of being created in a Desecrated area, provided the spell itself is cast on such an area) to an existing undead. Essentially, the undead is considered to have just been created by the caster for purposes of these abilities. However, this does not allow the caster to affect who the controller of the undead is. Mindless undead may be enhanced in this way provided their controller permits it. This may be used even on undead that the caster cannot create, such as vampires. This use of the spell is considered harmless.
This spell may also be used to remove enhancements, provided the caster is capable of applying those enhancements to undead he creates. This use of the spell is not harmless.
This spell may be applied to incorporeal undead by use of Spectral Hand cast immediately before beginning to cast Enhance Undead. This use overrides the normal duration of Spectral Hand, which must remain in contact with the target and vanishes as soon as the casting is over.
Material component: a fragment of bone, which is crushed.
Special: The caster must have either the Corpsecrafter feat or the Dread Necromancer Undead Mastery ability to cast this spell.

[GnomeWorks]

Ah, good ol' Book of Bad Latin...

The "Special" line seems unnecessary, someone without those abilities could cast this spell, it would just be pointless.

Other than that, seems pretty solid. Just lets you upgrade things that already exist, rather than force you to create them from scratch. Somewhat like upgrading magic items, rather than getting new ones.

[Alex12]

Ah, good ol' Book of Bad Latin...

The "Special" line seems unnecessary, someone without those abilities could cast this spell, it would just be pointless.

Not if it's happening in a Desecrated area.

Other than that, seems pretty solid. Just lets you upgrade things that already exist, rather than force you to create them from scratch. Somewhat like upgrading magic items, rather than getting new ones.

Also great for making alliances with, say, vampires.

[GnomeWorks]

Not if it's happening in a Desecrated area.

...fair enough.

I don't think it's necessary. Letting normal casters enhance their undead in a desecrated spell via a spell that takes an hour to cast is honestly not that big of a deal.

[Mithril Leaf]

So in our current campaign, my backup character plan is a Necropolitan Dread Necromancer, but the DM said I can't just get the effects of being created with Corpsecrafter without paying for them. This is how I plan on doing that.
I just wanted to get the playground's opinion on this. Broken? Not broken? A terrible idea?

Here's the thing about it all. I know all about making homebrew to get DM arbitrary stuff more legalish. It's seriously what nearly all my homebrew exists for, but anyways. You're clearly using it to boost necropolitans. You're basically saying that once you hit level 8 you get a bunch of free boosts because you made a homebrew spell. I'm not saying that's wrong, but lets call a horse a horse here. The point of this spell is to force a ruling one way. If it's a decently high op group, go right ahead.

[GoddessSune]

Way too powerful and broken. There are limits on the kind of undead that can be made, and enhanced, and this just throws that out the window. And adding endless abilities, changing them every hour is way too much. And the spell has no cost.

You need to bump it up a couple levels and add an expensive component so it can't be used all the time. Or maybe just make the spell effects temporary.

[Alex12]

Way too powerful and broken. There are limits on the kind of undead that can be made, and enhanced, and this just throws that out the window. And adding endless abilities, changing them every hour is way too much. And the spell has no cost.

You need to bump it up a couple levels and add an expensive component so it can't be used all the time. Or maybe just make the spell effects temporary.

Endless abilities? Not sure what you mean by that. It's only abilities you could apply to undead you actually created. You couldn't cast Animate Dead and say "I apply Corpsecrafter 1000 times, giving it 2000 hp per HD."
And if you lose control of those undead, or they were never under your control to begin with, then they still have that enhancement.
I figure the spell was invented by either a Necropolitan or a Vampire, who looked at those Corpsecrafted zombies and skeletons and thought "Man, I need to get me some of that."

[GoddessSune]

Endless abilities? Not sure what you mean by that. It's only abilities you could apply to undead you actually created.

It is easy enough for a spell caster to control undead lots of ways. Then they could cast this spell for every ability and feat they have to enhance the undead. And every time they get a couple levels and a new feat, they can just cast the spell again.

And you can only make a limited number of types of undead, so you can only apply your undead creation abilities to them. But with this spell, you can give them abilities to any undead. It just looks like too much.